U.S. patent application Ser. No. 479,009 discloses apparatus for conditioning the air in an enclosure by utilizing a direct contact air/brine heat exchanger in which enclosure air is directly contacted with brine from a reservoir for condensing water vapor in the enclosure onto the brine to form diluted brine. The diluted brine is regenerated in a fuel fired boiler producing steam that may be piped into an indirect contact heat exchanger located in the enclosure for the purpose of heating the air in the enclosure. Dilute brine from the direct contact heat exchanger is piped to the boiler through a counter-flow heat exchanger in which the dilute brine absorbs heat from, and thus cools, the concentrated brine extracted from the boiler. The resultant cooled concentrated brine is transferred to a reservoir from which brine is applied to the direct contact air/brine heat exchanger. With this arrangement, the temperature of the concentrated brine entering the direct contact air/brine heat exchanger is kept as low as possible. That is to say, the vapor pressure at the air/brine interface of the brine entering the direct contact air/brine heat exchanger will almost always be less than the vapor pressure of the air in the enclosure with the result that the brine entering the direct contact heat exchanger will be hygroscopic and will thus absorb moisture from the air.
An object of the present invention is to minimize the physical size of the apparatus described above, and to improve its efficiency, for example, by minimizing fuel consumption, and by increasing the amount of heat returned to the enclosure.